Grantee Research Project Results

Concentrated ambient particles alter myocardial blood flow during acute ischemia in conscious canines.

Citation:

Bartoli CRG, Wellenius GA, Coull BA, Akiyama I, Diaz EA, Lawrence J, Okabe K, Verrier RL, Godleski JJ. Concentrated ambient particles alter myocardial blood flow during acute ischemia in conscious canines. Environmental Health Perspectives 2009;117(3):333-337.

Abstract:

BACKGROUND: Experimental and observational studies have demonstrated that short-term exposure to ambient particulate matter (PM) exacerbates myocardial ischemia. OBJECTIVES: We conducted this study to investigate the effects of concentrated ambient particles (CAPs) on myocardial blood flow during myocardial ischemia in chronically instrumented conscious canines. METHODS: Eleven canines were instrumented with a balloon occluder around the left anterior descending coronary artery and catheters for determination of myocardial blood flow using fluorescent microspheres. Telemetric electrocardiographic and blood pressure monitoring was available for four of these animals. After recovery, we exposed animals by inhalation to 5 hr of either filtered air or CAPs (mean concentration+/-SD, 349.0+/-282.6 microg/m³ p<0.001) and was accompanied by a 13% (p<0.001) increase in coronary vascular resistance. Rate-pressure product, an index of myocardial oxygen demand, did not differ by exposure (p =0.90). CAPs effects on myocardial blood flow were significantly more pronounced in myocardium within or near the ischemic zone versus more remote myocardium (p interaction<0.001). CONCLUSIONS: These results suggest that PM exacerbates myocardial ischemia by increased coronary vascular resistance and decreased myocardial perfusion. Further studies are needed to elucidate the mechanism of these effects.